1. Field of the Invention
The present invention relates generally to a display apparatus for an automotive vehicle and more specifically to a head up display apparatus by which the driver can see display images projected from a projector and reflected from a reflector disposed in front of the windshield, as virtual images, in superimposition upon the outside view through the windshield.
2. Description of the Prior Art
The same applicant has recently proposed a novel head up display apparatus for an automotive vehicle which comprises a projector disposed at a ceiling of the automotive vehicle to project display images and a half reflector disposed on a dashboard of the vehicle to reflect the display images projected by the projector and to transmit the outside view to the driver, simultaneously. The half reflector is a half mirror or a hologram plate. The above display apparatus can provide stable display images without being subjected to external sunlight, being free from dimensional restriction due to small dashboard inside space and high in heat radiation efficiency.
In the above display apparatus, although the half reflector is designed so that the size becomes as small as possible, when the half reflector is disposed in front of the driver, since the frontward field of vision is obstructed, the presence of the half mirror is not preferable from a standpoint of safety in driving a vehicle.
To overcome this problem with safety, the half reflector is preferably disposed on the dashboard being a little dislocated from the driver's front toward the longitudinal vehicle center. In the above-mentioned arrangement of the half reflector, however, there still exists a problem in that the driver cannot appropriately see display images reflected from the half reflector when the driver's body is tilted inward or outward due to vehicle running along a sharp curved road or when the distance between the driver and the half reflector differs according to driver's physique.
The above-mentioned problems will be described in further detail hereinafter with reference to the attached drawings under DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS.